07 Feb 2012

Small Cells are the Key for LTE Deployment

One of the key elements to LTE deployment has always been the adoption of small cells. In order to provide the increased data capacity, not only is it necessary to have spectrum efficient radio technologies, but greater increases in capacity have always relied upon the reduction in cell sizes.

To achieve the reduction in cell sizes a variety of approaches are vying for supremacy. In the past femto-cells, possibly home-based have been seen as the major ways forwards, but comparatively few operators have been adopted them in a big way. At the same time many of the more traditional infrastructure manufacturers such as NSN, Ericsson and others have been pushing for small cell technology that forms part of the planned radio network. However this technology uses many of the same concepts as those in the more traditional femto space. As a result the Femto-Forum has been looking at the wider small cell technologies/

It is therefore interesting to note that the Femto Forum, the industry and operator association that supports femtocell deployment worldwide, has announced that they have seen a strong uptake of its small cell LTE APIs. This, they say, is showing that the vendor community is rapidly preparing the technology to meet the operator demand.

Figures released show that seventeen manufacturers have currently adopted the APIs for their upcoming LTE products. These companies include Airvana, AirWalk Communications, Broadcom, Cisco, Freescale, ip.access, mimoOn , Mindspeed, Picochip, Radisys, Tata Elxsi, Texas Instruments and Ubiquisys amongst others. Additionally, SK Telecom has also implemented the APIs in its LTE femtocell deployment. The LTE APIs enable interoperability between LTE femtocell semiconductors and protocol software from different vendors.

This adoption is being driven by LTE small cell commitments from operators around the world including China Mobile, Vodafone, SK Telecom and NTT DoCoMo. It is known that LTE as a technology in itself will not be able to provide the increase in data capacity required. This can only come from reducing the cell sizes so that spectrum re-use factors are greatly improved.

However to achieve this, much cheaper and more flexible cell technologies need to be adopted. This is happening in a large way to meet the expected demand, although the current economic climate has slowed the deployment. Additionally many operators who are deploying LTE are having teething troubles with their networks, as would be expected with any new technology.

This approach is backed by industry research and surveys from organisations including Informa Telecoms & Media who have found that 60% of operators believe small cells are more important than macrocells in LTE deployments. Small cells were also the comfortable winner in a Rethink Research survey of the most important features for LTE-Advanced.

“As operators plan LTE networks, small cells, including femtocells, could play a critical role in enabling the fastest possible data services in metropolitan and rural public spaces, as well as in private homes and offices,” said Alan Law, Chairman of the Femto Forum’s LTE SIG. “This positive uptake of the Forum’s LTE API is one more sign of the growing importance of small cells.”

“Where small cells once comprised a telecoms niche, they are now at the epicenter of mobile broadband thinking. The quick uptake of the Forum’s LTE API is further testament to this fact – vendors up and down the value chain are adopting the API to give themselves a time-to-market advantage and the ability to select best-in-class software and hardware – which don’t always come from the same source“ said Nick Johnson, CTO of ip.access and Chair of the Femto Forum’s Radio and Physical Layer Working Group, whose members originated the LTE API.

By enabling interoperability between different products, the Forum’s LTE APIs help create a more competitive marketplace by ensuring that small cell device manufacturers can cost-effectively source these critical components from multiple suppliers while also maximizing the market for semiconductor manufacturers.

The APIs address three fundamental functions: Physical Layer control, scheduling and network monitoring. Crucially, the APIs support vendors’ unique approaches to enable them to develop products that can be differentiated from each other, thereby developing the different business models required and supporting innovation, while helping ensure their solutions are compatible with all other femtocell components.

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